Alloy.



' 'in an admirable manner without great fric- UNITED STATES ALLOY.

PATENT OFFICE.

or PARIS, FRANCE;

SPECIFICATION formingpart of Letters Patent No. 648,652, dated May 1,1900. Application filed May 3, 1897. Berle-1N0. 6 34,944- (Nospecimens.)

To (11H Ii /mm. 17- um. on/awn].-

llo it known that I, LUUIS. BOUDREAUX, a subject of the .ltepublic ofFrance, residing at Paris, France, have invented certain new and usefullm provements in or Relating to Dynamo and Like ElectricalContact-Brushes, of which the following is a specification.

The electrical contact-brushes indispcn sable, for instance, for dynamosmust fulfil certain conditions. 'lheirconductivity'must be as great aspossible in order not to otter resistance to the passage of the current,while their friction on the commutator must be as little as possible. Itis obvious that a bar or block of copper, brass, or bronze wouldsatisfactorily answer the first, but'fwould be far I l'OIil satisfyingthe'second requirement. In order to realize the second condition, it hasbeen found 'necessary to divide the metal constituting the brushes andconstruct them in the form of metal strips, plates,wire leaves, netting,and powder. The great tenacity and extreme ductility of copper or itsusual alloys render indispensable the latter mode of making thebrushes,.whereby is avoided the excessive friction between thecommutator and brushes when made of a bar or block of copper or alloy ofgreat tenacity and ductility. I have discovered means quite differentfrom the mechanical division of 'the metal. 7

constituting the brushes whichwill satisfyv the above requirements. Thisconsists in modifying the molecular state of the metals employed, so asto lessen their tenacity and ductility, which is the object of thepresent invention. I add to copper or to its alloys a small proportionof bismuth, antimony, or cadmium, the nature ot' the resulting alloybeing quite diil'erent from those used hitherto. The fibrous structureof the copper becomes crystalline, a small percentage of bismuth,antimony, or cadmium rendering the coppervery, brittle. The behavior ofsuch an alloy on a commutator is quite difierent from that of. thealloys used hitherto. 'While the use -of copper results in considerableheating, owing to the great friction, the new alloy behaves tionalgripping Orheating. It may be compared to ametallic pojwder agglomeratedby fusion and having its molecules easily detachable by the commutator.

The alloys constituting mynew brush can be produced by simply meltingthe metals together or by placing the pulverized metals of suitablefineness in a mold and heating them under pressure to the temperaturerequired to melt them and produce the alloy.

, Although not confining myself to any definite or absolute proportionsof the'various metals, I prefer to use alloys of the followingcomposition For comm utators with sectors of red copper, two gramsbismuth, three grams cadmium, fifteen grams antimony, with one kilogramof commercial copper.

For commutato s with sectors of hard bronze, four grams bismuth, sixgrams cadmium, thirty grams-antimony, ,with one kilogram of commercialcopper.

For comm utators w grams bismuth, nine grams cadmium, fortyfive, gramsantimony, with one kilogram of commercial copper.

The antimony, bismuth, and cadmium are melted together, and theresulting alloy is added to the copper in the proportions hereinbeforespecified.

While an alloy having any of the propertionsabove recited will operatewith a dynamo having any of the peculiarities referred to, I haveascertained by experiment that better-results are obtained by varying.the proportions of the constituent ingredients according to thecharacter of the commutator in connection with which the brush is to beused.

I claim as my invention- I Anzalloy for use as described, consistingessentially of copper, bismuth, cadmium and antimony.

In witnesswhereot' I have hereto set my hand in the presence of the twosubscribing witnesses.

LOUIS BOUDREAUX.

Witnesses:

Louis SULLIGER,

E uwAnn I. MACLEAN.

ith sectors of steel, six

